I'm facing the same issue as this makes HAR files useless for me. I'll let you know if I figure out a way around this in Edge or Chrome.

I'm now thinking that I may have to rely on Fiddler from now on. I personally use Fiddler Classic because it's free, but it's also not actively being developed anymore. They also offer their new and subscription-based Fiddler Everywhere.

Anyway, for Fiddler Classic, you can download it here:

https://www.telerik.com/fiddler/fiddler-classic

Once you have it installed, you can configure Fiddler to decrypt HTTPS traffic following their documentation here:

https://docs.telerik.com/fiddler/configure-fiddler/tasks/decrypthttps

The only down-side of Fiddler versus the Developer Tools is that it's not isolated to one browser tab, let alone one application. If you have multiple 'things' like additional browser tabs and applications open (i.e. Outlook, Teams, etc.), you're going to see requests from these other sources peppered into your network trace.